Cellular construction for aircraft pontoons



Jan. 28, v1936. N ATWQQD 2,029,215

CELLULAR CONSTRUCTION FOR AIRCRAFT PONTONS Filed Sept. 14, 1934 lu/vmbo@ Harig uwo ad.

atented Jan. i936 PATENT QFFICE CELLULAR CONSTRUCTION FOB. AIRCRAFT PONTOONS 4 Claims.

This invention relates to hydro-airplanes, and more particularly to the construction of the pontoons thereof.

The object of the invention is to provide a pontoon of cellular or honeycomb construction, thereby decreasing the weight of the pontoon and increasing its strength and stability.

A further object of the invention is to provide a. pontoon, the water contacting surface of which decreases in proportion to the rate of speed or lifting power of the plane.

A further object is to provide a pontoon formed of hermetically sealed laminated tubular members, each constructed of brous material such as natural wood veneer strips wound in superposed spiral layers and impregnated with an acetone solution containing cellulosic plastic material,

said tubular members being assembled to conform to the shape or contour of a selected pontoon with their adjacent faces in intimate bonding contact with each other so as to form an integral built up honeycomb structure.

A further object is to provide the tubular members at the bottom of the pontoon with a waterproof surfacing material and to arrange said tubular members in stepped formation both longitudinally and transversely vof the pontoon so as to present water contacting surfaces of different areas and levels.

A still furtherobject of the invention is generally to improve this class of devices so as to increase their utility, durability and ei'liciency.

In the accompanying drawing forming a part of this specication and in which similar numerals of reference indicate corresponding parts in all the iigureswof the drawing:

Figure 1 is a side elevation ofa hydro-airplane provided with a pontoon'constructed in accordance with the present invention.

Figure 2 is a vertical sectional view taken on the line 2-2 of Figure 1.

Figure 3 is an enlarged vertical sectional view showing how the tubular members are assembled. Figure 4 is an enlarged detail vertical sectional view showing the bonding= vaction between the parts.

In the -accompanying drawing, 5 indicatesNa hydro-airplane of any well-known or conventional type and including in its structure a boat body or fuselage 6, wings 1, rudder 8, and propeller 9, the body or fuselage being provided with hangers I0 to which are lattached my improved pontoons II.

In accordance with the present invention, I propose to construct the pontoon entirely oi' independent laminated tubular members I 2 preferably straight throughout their entire lengths and arranged side by side in intimate bonding contact with each other so as to form a hollow integral reinforced honeycomb structure, thereby 5 rendering the pontoon light in weight, while, at the same time, giving it the desired strength and stability. The tubular, members I2 are each preferably formed from a strip or strips of natural wood veneer impregnated with an acetone 10 solution containing a small percentage of cellulosic plastic material such as cellulose acetate, cellulose nitrate or cellulose ester. These impregnated strips are wound in superposed spiral layers over a suitable shaping mandrel to form 15 laminated tubes of the desired length and cross sectional formation, as fully set forth and described in my co-pending application, led in the United States Patent Ofce on September 14, 1934, and bearing Serial No. 744,070.

In fabricating a pontoon, the laminated tubes are sprayed, coated or otherwise covered with the acetone solution and' while the exterior surfaces of the tubes are 'still moist or Wet, said tubes are placed on suitable finishing mandrels and as- 25 sembled side by side in superposed relation to conform to the shape of alselected style or type of pontoon with adjacent tubes in intimate bonding contact with each other, thus providing a hollow structure the top, bottom and sides of 30 which are` formed of inner and outer rows or layers of tubular members constituting inner and outer walls. `'Ihe structure thus formed is then subjected to the conjunctive action of heat and pressure to eilect the cooking thereof. The bot- 35 tom of the pontoon is preferably stepped longitudinally, as indicated at I3, and in assembling the tubular members constituting said bottom, said tubes are also stepped transversely, as indicated at'I4 in Figure 2 of the drawing/so that 40 the bottom of the pontoon is stepped both longitudinally and transversely. By constructing the bottom of the pontoon in this manner, the effectivewater contacting surface of said bottom decreases in proportion to the rate of speed or lift- 45 ing power of the hydro-airplane, thereby presenting less frictional resistance to thesurface of the water and, consequently, enabling thepilot to make a quicker and safer take-,off and landing than heretofore. The bottom of the pontoon at its'junction with the side walls I5 thereof is preferably reinforced and strengthened by the provision of interior auxiliary tubes I6 arranged -in stepped formation and which tubes are intimately bonded to the sidewalls and bottom of the pontoon and'to each other in -the manner previously set forth. Other auxiliary tubes l1,

also preferably arranged in stepped relation, serve to connect and reinforce the side walls and By reference to Figure 4 of the drawing, it will be noted that the cellulosic plastic material |19 when subjected to the .action of heat and pressure further impregnates and lls the pores and interstices of the wood veneer and conjunctively insures an effective bond between the parts and forms, in eifect, an integral, honeycomb structure capable of sustaining severe landing impacts, as well as tortional strains and stresses. If desired, the body of the pontoon may be provided with an exterior coating of cellulosic plastic material so as to be sure that all exposed surfaces are kcovered and provide a hard protective covering or jacket for the pontoon. By using cellulosic plastic material which has been dissolved in acetate to form an ,acetone solution, the acetate can be removed by a process of evaporation, leaving the cellulosic plastic material in its original chemical structure. Therefore, the cellulosic plastic material can be specifically applied again and again, layer upon layer upon 'the cellulosic plastic surfaces of thetubular members or exterior surface of the pontoon so as to cover and reinforce the same with a like chemical structure and the parts welded and integrated together into one homogeneous plastic structure by the mere application of heat and without liability of charcoaling or carameling the fibrous material-constituting the reinforcing lamina and, consequently, without reducing the inherent strength of said reinforcing material.

The tubular members constituting the waterA contacting surface of the pontoon are preferably constructed with their exposed surfaces coated or otherwise provided with an exterior coating or layer of waterproof material, preferably rubber, as indicated at 20 in Figure 4 of the drawing, and this rubber coating 20 is intimately combined with and eiectively bonded to the tubes so as to constitute an integral part thereof and prevent scaling or peeling of the rubber by friction due to water conditions. Furthermore, as the tubular members are hermetically sealed both individually and collectively, it follows that water and moisture cannot obtain access to the interior of the-tubes and cause deterioration thereof or detract from the buoyancy of the pontoon.

It will, of course, be understood that the pontoons may be made in different sizes and' shapes and the tubular members may be of unitary construction or fabricated with any desired number of laminations without departing from the spirit of the invention.

Having thus described the invention, what is claimed as new is:

1. A pontoon for hydro-airplanes comprising a hollow structural unit formed of laminated tubu- .lar members straight throughout their lengths and disposed side by side in superposed layers and intimately bonded' together to form reinforced top, bottom and side walls, and auxiliary tubular members disposed within the hollow structure at the intersection of adjacent walls and bonded to said adjacent walls.

2. A pontoon forfhydro-airplanes comprising a` hollow integral honeycomb structure formed of laminated tubular members straight throughout their lengths and treated with cellulosic plastic material, said tubular members being disposed side by side in superposed layers and intimately united and bonded together, the tubular members at the bottom of the pontoon being stepped both longitudinally and transversely thereof and coated with water-proof material, and auxiliary tubular members disposed in stepped relation within the hollow body at the intersection of adjacent walls thereof and bonded to said adjacent Walls.

3. A ntoon for hydro-airplanes comprising a hollow 1ntegral honeycomb structure formed of laminated tubular members straight throughout their entire lengths and Ahaving their opposite ends hermetically sealed, said tubular members being disposed side by side in superposed layers and securely bonded together to form inner and outer side, top and bottom walls, certain of the tubular members at'the bottom ofthe pontoon being offset longitudinally and transversely with respect tosaid bottom to form steps, and auxiliary tubular members disposed in stepped relation wallsv each consisting of inner and'outer tubularv c members, the tubular'members at the bottom of the pontoon being stepped both longitudinally and transversely thereof. 

